How write a recursive print program

Question

Gurus,

I want to know how to write a recursive function that prints

1
12
123
1234
...
......

For eg: display(4) should print

Answer 1

Just for fun, here's a purely recursive solution. It's in python, which is practically pseudocode anyway. (Non-pythonic newlines are for clarity).

def loop(max, row=1, col=1):
    if col <= row:
        print col,
        loop(max, row, col+1)
    elif row < max:
        print "\n",
        loop(max, row+1, 1)
    else:
        print "\n",

Answer 2

void display(int k)
    {
         if (k < 1) { return; }
         display(k-1);
         for (int i = 1; i <= k; i++)
         {
         cout << i;
         }
         cout << endl;

    }


    int main()
    {
        int a = 4;
        display(a);
        return 0;
    }